Search Publications
A Chandra X-ray Observatory Study of PSR J1740-5340 and Candidate Millisecond Pulsars in the Globular Cluster NGC 6397
Bogdanov, Slavko; Heinke, Craig O.; Cohn, Haldan N. +3 more
We present a deep Chandra X-ray Observatory study of the peculiar binary radio millisecond pulsar (MSP) PSR J1740-5340 and candidate millisecond pulsars in the globular cluster NGC 6397. The X-rays from PSR J1740-5340 appear to be non-thermal and exhibit variability at the binary period. These properties suggest the presence of a relativistic intr…
Specular reflection on Titan: Liquids in Kraken Mare
Sotin, Christophe; Barnes, Jason W.; Soderblom, Jason M. +12 more
After more than 50 close flybys of Titan by the Cassini spacecraft, it has become evident that features similar in morphology to terrestrial lakes and seas exist in Titan's polar regions. As Titan progresses into northern spring, the much more numerous and larger lakes and seas in the north-polar region suggested by Cassini RADAR data, are becomin…
Magnetic Bright Points in the Quiet Sun
Sánchez Almeida, J.; Del Moro, D.; Bonet, J. A. +1 more
We present a visual determination of the number of bright points (BPs) existing in the quiet Sun, which are structures though to trace intense kG magnetic concentrations. The measurement is based on a 0farcs1 angular resolution G-band movie obtained with the Swedish Solar Telescope at the solar disk center. We find 0.97 BPs Mm-2, which …
INTEGRAL results on supergiant fast X-ray transients and accretion mechanism interpretation: ionization effect and formation of transient accretion discs
Sidoli, L.; Ducci, L.; Paizis, A.
We performed a systematic analysis of all INTEGRAL observations from 2003 to 2009 of 14 supergiant fast X-ray transients (SFXTs), implying a net exposure time of about 30 Ms. For each source we obtained light curves and spectra (3-100 keV), discovering several new outbursts. We discuss the X-ray behaviour of SFXTs emerging from our analysis in the…
Earth-Moon-Mars Radiation Environment Module framework
Schwadron, N. A.; Posner, A.; Dayeh, M. A. +11 more
We are preparing to return humans to the Moon and setting the stage for exploration to Mars and beyond. However, it is unclear if long missions outside of low-Earth orbit can be accomplished with acceptable risk. The central objective of a new modeling project, the Earth-Moon-Mars Radiation Exposure Module (EMMREM), is to develop and validate a nu…
The reversal of the rotational modulation rates of the north and south components of Saturn kilometric radiation near equinox
Gurnett, D. A.; Persoon, A. M.; Kurth, W. S. +5 more
It has been known for many years that Saturn emits intense radio emissions at kilometer wavelengths and that this radiation is modulated by the rotation of the planet at a rate that varies slowly on time scales of years. Recently it has been shown that the radio emission consists of two components that have different rotational modulation rates, o…
Multispacecraft observation of electron pitch angle distributions in magnetotail reconnection
Wang, Shui; Huang, Can; Lu, Quanming +1 more
In this paper, we present Cluster observations of a magnetotail reconnection event without the presence of an obvious guide magnetic field and analyze electron pitch angle distributions in the vicinity of the X line and the outflow region, respectively. In the vicinity of the X line, at lower energies the distributions are highly anisotropic (fiel…
Evolution of the Solar Activity Over Time and Effects on Planetary Atmospheres. II. κ1 Ceti, an Analog of the Sun when Life Arose on Earth
Ribas, I.; de Medeiros, J. R.; Porto de Mello, G. F. +6 more
The early evolution of Earth's atmosphere and the origin of life took place at a time when physical conditions at the Earth were radically different from its present state. The radiative input from the Sun was much enhanced in the high-energy spectral domain, and in order to model early planetary atmospheres in detail, a knowledge of the solar rad…
Spectral variability and reverberation time delays in the Suzaku X-ray spectrum of NGC 4051
Turner, T. J.; Kraemer, S. B.; Crenshaw, D. M. +3 more
Long-exposure Suzaku X-ray observations of the nearby active galaxy NGC 4051 from 2005 and 2008 are analysed, in an attempt to reach a self-consistent understanding of both the spectral variability on long time-scales and the broad-band variability at high time resolution. The techniques of principal components analysis and a maximum likelihood me…
The baryonic content and Tully-Fisher relation at z ~ 0.6
Yang, Y.; Flores, H.; Hammer, F. +3 more
Context. Using the multi-integral-field spectrograph GIRAFFE at VLT, we previsouly derived the stellar-mass Tully-Fisher Relation (smTFR) at z ~ 0.6 for a representative sample of 63 emission-line galaxies. We found that the distant relation is systematically offset by roughly a factor of two toward lower masses from the local relation.
Aims:…